🐶 Smart Pet Feeder using ESP32 + Servo + Serial WiFi Terminal

• Connect ESP32 to WiFi

• Create a WiFi TCP Server

• Control gate from mobile app

• Show real-time status in terminal

📦 Components Required

• ESP32

• SG90 Servo Motor

• External 5V supply (recommended)

• WiFi connection (Hotspot or Router)

• Android App: Serial WiFi Terminal (TCP Client app)

Recommended app:

• “TCP Telnet Terminal”

• “Serial WiFi Terminal”

• Any TCP Client app

🔌 Circuit Connections

Servo → ESP32

⚠ IMPORTANT:
Connect External GND and ESP32 GND together

🌐 Working Principle

1. ESP32 connects to WiFi

2. Creates TCP server (Port 23)

3. Mobile connects using IP address

4. User sends:

   • OPEN

   • CLOSE

5. ESP32 controls servo

6. Status shown in app

💻 Complete ESP32 WiFi Terminal Code

Copy and paste into Arduino IDE:

#include <WiFi.h>
#include <ESP32Servo.h>

const char* ssid = "YOUR_WIFI_NAME";
const char* password = "YOUR_WIFI_PASSWORD";

WiFiServer server(23); // Port 23 (Telnet)

Servo feederServo;
const int servoPin = 18;
int gateState = 0; // 0 = Closed, 1 = Open

void setup() {
Serial.begin(115200);

feederServo.attach(servoPin);
feederServo.write(0); // Start closed

Serial.println("Connecting to WiFi...");
WiFi.begin(ssid, password);

while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}

Serial.println("\nWiFi Connected!");
Serial.print("IP Address: ");
Serial.println(WiFi.localIP());

server.begin();
Serial.println("Server Started");
}

void loop() {

WiFiClient client = server.available();

if (client) {
Serial.println("Client Connected");

while (client.connected()) {

if (client.available()) {

String command = client.readStringUntil('\n');
command.trim();

if (command.equalsIgnoreCase("OPEN")) {
openGate(client);
}
else if (command.equalsIgnoreCase("CLOSE")) {
closeGate(client);
}
else {
client.println("Invalid Command! Send OPEN or CLOSE");
}
}
}

client.stop();
Serial.println("Client Disconnected");
}
}

void openGate(WiFiClient client) {
feederServo.write(90);
gateState = 1;

client.println("Food Gate is OPEN");
Serial.println("Gate Opened");
}

void closeGate(WiFiClient client) {
feederServo.write(0);
gateState = 0;

client.println("Food Gate is CLOSED");
Serial.println("Gate Closed");
}

🧠 Code Explanation (Concept Wise)

1️⃣ Include Libraries

• WiFi.h → Connect ESP32 to WiFi

• ESP32Servo → Control servo motor

2️⃣ WiFi Credentials

Replace with:

• Your router name

• Your router password

3️⃣ Create Server

Port 23 is Telnet port.
Mobile app connects using:

IP + Port 23

4️⃣ Connect to WiFi

Loop waits until connected.

Then prints:

You will use this IP in mobile app.

5️⃣ Accept Client

Checks if someone connected from mobile.

6️⃣ Read Command

Reads message sent from mobile.

Example:
OPEN
CLOSE

7️⃣ Control Servo

OPEN → 90°
CLOSE → 0°

📱 How to Use Mobile App

1. Upload code

2. Open Serial Monitor

3. Note IP address

4. Install TCP Client app

5. Enter:

   • Host: (ESP32 IP)

   • Port: 23

6. Connect

Now type:

Gate opens.

Gate closes.

📟 Example Output in App

🎯 What Students Learn

• WiFi networking

• TCP Server concept

• IP address usage

• Remote control via local network

• Client-Server communication

• IoT fundamentals

🚀 Upgrade Ideas (Professional Level)

• 🌍 Global control using Port Forwarding

• 🌐 Web browser control (no app required)

• 📊 Web dashboard

• 🕒 Auto feeding timer

• 📦 Food level sensor integration

• 📱 Custom Android app